Process of manufacturing brake-shoe keys.



YTH. G BRAKE SHOE KEYS.

Patepted Jan. 30, 1912.

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Xmmmkn muuuy l W. D. F PROCESS 0F MANUPAGT I APPLICATION FILEDVOOTI,1910. 1,01 6,068.

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WILLIAM n. ronsYTH. Yor YoUNesTo-wn, onto'.

vrnocnssl F MANUFACTURING BRAKE-snor. KEYS.

Speciicaton of Letters '.Patent.

' Patented Jan. 30,1912".

Application led October 31, 1910. ,A Serial No. 589,966.

be effective in producing brake-shoe keys yat minimum cost.

In the accompanying drawing, Figure l Ais a plan view of a key-blank cutfrom the rolled bar. Fig. 2 is a side elevation of the same. Fig. 3 is across section of the rolls to form rolled bars such as shownforeshortened in Fig. 5. Fig. 4 is a side elevation of a completedbrake-shoe key. Fig. 5 is a foreshortened plan of the rolled bar fromwhich the key blanks are cut. Fig.-6 is a longitudinal section on theline 6-6 of Fig. 5. Fig. 7 is a foreshortened plan view of a portion ofa development of the peripheryy of one of the rolls by which the barshown in Fi-g.,5 is rolled. Fig. 8 is a cross section of this roll onthe line 8-8 of Fig. 7. Fig. 9 is a left end view of the key shown inFig. 4.

Similar reference characters refer to like parts throughout the -severalviews.

The usual manner of' producing brake-shoeV keys is to form abar of evencross-section into a'wedge and then trim oft1 the edges of the wedgeuntil the proper width is attained. This results in waste, firstVbecause the key is of unnecessary'weight; and second, the metal trimmedfrom the wedges is of less value per pound than the original material.The process employed to form the key shown in Figs. 4 and 9., ashereinafter described, results in no waste of material by trimming, andavoids unnecessary weight in the finished key. While keys have been castin proper form, cast keys are either too expensive or worthless.

The process forming the basis of this invention consists in rolling abar l by means unique rolls, shearing the bar to form blanks 2, and thenbending the blanks to form keys The rolls for formino' the bar shown inFigs. 5 and may be of any proper diameter, so long as the circumferenceof the grooving roll equals a multiple of double the length of a keyblank. One roll is formed with the usual groove and the other with the.circumferential rib,l employed to produce -barsv of exact sizes. Thebottom of the groove of one roll or the top of the rib of the otherroll' is formed with projections or dies 3, which are diamond-shaped inplan and substantially*semi-circular in cross section at their middleportions. ln the drawings, `the projections are shown at the bottom ofthe groove. These projections taper toward their ends, not because theradial height ofthe projections changes, but because the radial heightsof the bottoms of the spaces between the projections and the walls 14change.

Considering the circumference of the cylindrical portion 4 of the roll 5of Fig. 3, developed into va plane 9, Figs. 7 and 8, then the highestsurface of the projections 3 will form a line 10, in Fig. 8. On eachsideof these projections are inclines 11.. The opposite roll 12 has acylindrical projection 13 which enters between the walls 14 of thegroove in the first roll, and in the development in Fig. 8, forms thedotted line l5.

When a bar of metal of suii'icient size is passed between the rolls, theedges will be formed into two consecutive series of in clines 16, 5 and6) which inclines are f separated .by round-bottomed grooves 17 havingtapering ends, whose deepest depressions are at .the apexes of theinclines. T he blankbar lis then formed at one pass through the rolls.The blank-bar l is next sheared trans,-

versely at the tops and bottoms of the inclines 16,:on the lines Lf-aand b-b, Fig. 5, thus forming the blanks 2, having a thin lower end,'and a thick upper end which is provided with a groove 19. The blank isthen bent to conform to the curve of the brake-shoe and to produce ahead 20. There is no waste of material either in the forming of the key7, nor in the key itself, and as all the steps may be carriedout bymeans of machines, the labor cost is very small.

The form of the rolls, the depth and cross section of the groove, andthe general proportions may be changed without departf ing from thespirit of my invention.

Having now explained my process, what I claim as my invention anddesireto secure by Letters Patent is The process of manufacturing Abrake-shoekeys'wln'ch consists in so rolling a bar as to `inclines, andsemi-circuler, tapering, 1ong i' tudina-l grooves Whose deepestdepresslons are "at 'the apexes Of sald lnclinesythenshearlng form onone of its Surfaces a' plurality of e predetermined curvature and toforma conseeutve nclines ascending and descending from apexe's located atthe` endsof said said bar transversely at the apex .of said inclines andagain. midway between the apexes ,f said nclines to form key-blanks;

and then bending blanks so as to give them heed at the thick end. I

,In testimony whereof, I have signed this specication in the presence oftwo subscrb ing Witnesses.

l VILLIAM D. F ORSYTH. In the presence of A l ELIZABETH M. BROWN,

GEORGE T. WILSON.

Copies ofthis patent may be obtanedfor live cents each, by addressingtheComnrissier of Patents. t Washington, D. C.

